Appropriate communication wires need to be accommodated to achieve electrical connection when using communications apparatuses such as computers, modems, telephones, or facsimile apparatuses. To avoid entanglement of wire due to a too-long length of external wire or inconvenience of use due to a too-short length of external wire, several kinds of wire-winding boxes applicable to various kinds of communications apparatuses have been proposed. A general conventional wire-winding box comprises a casing, a rotary disk, a spiral reed, and a communication wire. The spiral reed and the rotary disk are fixedly joined to let the communication wire wound on the rotary disk have resilient restoring capability. Because electric connection needs to be kept on the communication wire during the process of rotation when the communication wire is pulled out or wound back, part of wire-winding boxes will be installed with conductive devices of different structures. For instance, electric connection on the communication wire will not be affected when the rotary disk rotates by installing a plurality of concentric conductive rings of different radii on the disk face of the rotary disk and a plurality of conductive elements like conductive resilient leaves or steel balls corresponding to the conductive rings on another rotary disk or the casing. However, because there are so many components of these conductive rings and conductive resilient leaves or steel balls, and each component has a very small volume, the assembly is time-consuming and difficult. Moreover, bad contact or other failures may easily arise in use.
Besides, a communication wire may show a tight state due to resiliency of the spiral reed when pulled out from a conventional wire-winding box so that a proper length of the communication wire cannot be kept outside, resulting in much trouble in use. To resolve this problem, in some wire-winding boxes, a swing piece capable of resiliently swinging is utilized, and gaps and buckling grooves disposed at the periphery of a rotary disk are matched, thereby accomplishing winding or positioning function.
As shown in FIGS. 1 and 2, a prior art short wire length wire-winding box is illustrated. This prior art wire-winding box includes a casing 10a, a rotary disk 11a, a communication wire 12a and a spiral reed (not shown). The casing 10a having a receiving groove 13a therein. The receiving groove 13a is installed with a pivotal shaft 14a. The lateral sides of the pivotal shaft 14a and the casing 10a are installed with wire outlets 15a and 16a. The rotary disk 11a is received in the receiving groove 13a and is pivotally engaged to the pivotal shaft 14a for rotation. One lateral side thereof is installed with a ring 17a. The ring 17a is installed with a slot 18a. One wire end of the communication wire 12a passes through the wire outlet 15a of the pivotal shaft, while other part of the communication wire 12a is firstly bent through a proper angle and then pulled to the slot 18a of the ring 17a. Subsequently, it protrudes out from the other wire outlet 16a of the casing 10a. When the rotary disk 11a rotates, the communication wire 12a may slide on the ring 17a timely so as to be wound around the pivotal shaft 14a and the ring 17a. The spiral reed (not shown) is used to provide restoring elasticity to the rotary disk 11a. 
The above short wire length wire-winding box can greatly reduce the number of subassemblies, can facilitate assembly and mass production, and can let the communication wire be simultaneously wound around the pivotal shaft and the ring in special interactive way when the rotary disk rotates. Thereby, it is not necessary to install complicated and delicate conductive subassemblies in the wire-winding box so as to simplify assembly.
However, since as the communication wire 12a is pulled out directly from the wire-winding box, the communication wire 12a wound on the pivotal shaft 14a (inner circle) will become looser and looser by a further pulling force, i.e., the communication wire 12a on the pivotal shaft 14a will disperse (referring to FIG. 2) so that part of the communication wire 12a on the inner circle is difficult to be received. Therefore, other positioning device (not shown) is necessary for positioning the communication wire 12a on the pivotal shaft 14a. 
Furthermore, since as the communication wire 12a is wound back to the wire-winding box, the pivotal shaft 14a (inner circle) and the ring 17a (outer circle) are wound by the communication wire 12a. The inner and outer circles need spiral reeds and thus, the spiral reed needs a large elastic force. Moreover, a large friction force is formed between different parts of the communication wire, and thus different parts of the communication wire 12a will be hindered by one another.